1. Field of the Invention
The invention pertains to thermostatically controlled fittings for internal combustion engine coolant systems which includes a closable bypass passage which permits coolant flow therethrough during filling of the engine coolant system to eliminate trapped air pockets.
2. Description of the Related Art
Internal combustion engines utilize thermostatically controlled valves to regulate the coolant temperature for various purposes. Such thermostatic valves are closed when the engine is cold to prevent coolant circulation and accelerate the heating of the engine block to improve engine operating characteristics, and accelerate the heating of the vehicle occupant climate control system. Upon the engine coolant reaching a predetermined elevated temperature, the thermostatic valve begins to open permitting the coolant to circulate through a cooling radiator to achieve the desired coolant temperature during normal engine operation.
Such thermostatic valves may be incorporated into various parts of the engine coolant system. Usually, thermostatic valves are incorporated into hose lines or hose fittings for ease of assembly and replacement.
When an internal combustion engine is initially assembled, it is, of course, cold and the thermostatic valves in the coolant system will be closed. As the coolant is introduced into the coolant system, the closed thermostatic valve will cause air to be trapped within the coolant system preventing the coolant system from being fully charged with coolant, and it is often necessary to use expensive "bleeding" procedures to permit entrapped air to escape from the coolant system during the initial engine coolant charging. Due to the complexity of modern internal combustion engines, the confinement and clearance problems existing in the engine compartment, especially in front wheel drive vehicles, the loosening of components within the coolant system to permit the bleeding of entrapped air is difficult and time consuming, and once the bleeding has been completed, it is possible for the mechanic to overlook the need to fully restore the coolant system to its liquid tight condition resulting in liquid loss during engine operation.